2010 年 26 巻 4 号 p. 417-423
A nitrate ion-selective electrode (NO3−-ISE) has been developed based on tetradodecylammonium bromide as an anion exchanger and 2-nitrophenyl octyl ether as a plasticizer. The NO3−-ISE shows an almost Nernstian response to nitrate ion over a concentration range between 1.0 × 10−6 and 1.0 × 10−1 M, with an anionic slope of −57.7 ± 0.7 mV/decade. The selectivity coefficients of the NO3−-ISE for nitrate ion against chloride and sulfate (log kpotNO3−Cl− = −2.42 and log kpotNO3−SO42− = −4.33) were obtained. A microfluidic polymer chip was fabricated using polystyrene plates and stainless-steel wires as a template for the channel. The microfluidic polymer chip is composed of a mixing chip and a NO3−-ISE detector chip. The microfluidic polymer chip, integrated with a NO3−-ISE detector consisting of the NO3−-ISE and a Na+-ISE as a reference electrode, showed an almost Nernstian response to nitrate ion over a concentration range between 1.0 × 10−5 and 1.0 × 10−1 M, with an anionic slope of −54.3 ± 1.3 mV/decade. The microfluidic polymer chip was then applied to the determination of nitrate ion in environmental water samples, such as a tap water, a well-water sample and water for agricultural use.
